共查询到20条相似文献,搜索用时 31 毫秒
1.
J. Ma Z. H. Hou H. W. Xin 《The European Physical Journal B - Condensed Matter and Complex Systems》2009,69(1):101-107
We study the effect of recycled noise, generated by the superposition of a
primary Gaussian noise source with a second component of constant delay, in
a parameter region below the threshold of supercritical Hopf bifurcation, by
focussing on the performance of noise induced oscillations and coherence
resonance. For fixed noise intensity, the amplitude and signal-to-noise
ratio of the oscillation show periodic dependences on the delay time. The
optimal noise intensity for the occurrence of coherence resonance also shows
a periodic dependence on the delay. A theoretical analysis based on the
stochastic normal form theory is presented, which qualitatively reproduces
the simulation results with good agreement. This work presents a possible
strategy for controlling noise induced oscillations and coherence resonance
by deliberately adjusting the parameters of the recycled noise. 相似文献
2.
Igor Schreiber Martin Holodniok Milan Kubíček Miloš Marek 《Journal of statistical physics》1986,43(3-4):489-519
3.
F. Curbis A. Antoniazzi G. De Ninno D. Fanelli 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,59(4):527-533
Single-pass free-electron lasers constitute an example of systems with
long-range interactions. The light-particle interplay leading to the
power growth and successive relaxation towards a quasi-stationary state
is governed by the Vlasov equation. A maximum entropy principle inspired to Lynden-Bell's theory of
“violent relaxation" for the Vlasov equation can be invoked
to analytically
characterize the behaviour of the saturated system.
In particular, we here concentrate on the case of
coherent harmonic generation obtained from an externally seeded
free-electron laser and provide a simple strategy to predict the
laser intensity as well as the final electron-beam
energy distribution. 相似文献
4.
P. Mathey M. Grapinet H. R. Jauslin B. Sturman D. Rytz S. Odoulov 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2006,39(3):445-451
A general analysis of the threshold behavior for the
photorefractive semi-linear oscillator is performed within the
linear approximation on the basis of the classical wave-coupling
model. This analysis shows that the well known particular results
on the frequency degenerate oscillation are valid only within a
restricted range of the external parameters. The theory specifies
the conditions for onset and properties of the frequency
non-degenerate oscillations, including the necessary values of the
coupling strength, pump intensity ratio, the increments of the
instability, and the frequency splits. Important generalizations
of the basic model are considered. 相似文献
5.
G. De Ninno D. Fanelli C. Bruni M.E. Couprie 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,22(2):269-277
The temporal dynamics of a storage-ring Free Electron Laser is here investigated with particular attention to the case in
which an external modulation is applied to the laser-electron beam detuning. The system is shown to produce bifurcations as
well as chaotic regimes. The peculiarities of this phenomenon with respect to the analogous behaviour displayed by conventional
laser sources are pointed out. Theoretical results, obtained by means of a phenomenological model reproducing the evolution
of the main statistical parameters of the system, are shown to be in a good agreement with experiments carried out on the
Super-ACO Free Electron Laser.
Received 27 March 2002 / Received in final form 17 July 2002 Published online 21 January 2003
RID="a"
ID="a"Present address: Sincrotone Trieste, 34012 Trieste, Italy.
RID="b"
ID="b"e-mail: fanelli@nada.kth.se 相似文献
6.
In this work, we study the effects related to the creation of electron/hole pairs via application of an external electric field that acts on a pristine trans-polyacetylene molecular chain at zero-temperature. This phenomenon is termed Schwinger–Landau–Zener (SLZ) effect and arises when a physical system, which can even be the vacuum, is under the action of a strong, static and spatially homogeneous electric field. Initially, we investigate how the electrical conductivity of the polyacetylene changes with the applied field, by considering the carriers production as well as the variation of the interband gap according to certain ab initio models. Next, we analyse the competition between the SLZ effect and another one associated with the incidence of an uniform electric field on one-dimensional crystals – the Bloch oscillations. We evaluate the conditions in which these latter can be destroyed by the particles created through the same field that induces them, and verify the possibility of occurrence of the Bloch oscillations inside the trans-polyacetylene with frequencies equal to or higher than the terahertz scale. 相似文献
7.
Generation of a Super Strong Attosecond Pulse from an Atomic Superposition State Irradiated by a Shape-Optimized Short Pulse
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Using a linearly polarized, phase-stabilized 3-fs driving pulse of 800 nm central wavelength shape-optimized on its'ascending edge by its an amplitude-reduced pulse irradiating on a superposition state of the helium atom, we demonstrate theoretically the generation of a super strong isolated 176-attosecond pulse in the spectral region of 93-124 eV. The unusually high intensity of this attosecond pulse is marked by the Rabi-like oscillations emerging in the time-dependent populations of the ground state and the continuum during the occurrence of the electron recombination, which is for the first time observed in this work. 相似文献
8.
M.-C. Chung A. R. Kolovsky 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,47(3):421-425
We consider a Bose-Einstein condensate of ultracold atoms loaded
into a square optical lattice and subject to a static force. For
vanishing atom-atom interactions the atoms perform periodic Bloch
oscillations for arbitrary direction of the force. We study
stability of these oscillations for non-vanishing interactions,
which is shown to depend on an alignment of the force vector with
respect to the lattice crystallographic axes. If the force is
aligned along any of the axes, the mean field approach can be used
to identify the stability conditions. On the contrary, for a
misaligned force one has to employ the microscopic approach, which
predicts periodic modulation of Bloch oscillations in the limit of a
large forcing. 相似文献
9.
C.H. Miwadinou A.V. Monwanou J. Yovogan L.A. Hinvi P.R. Nwagoum Tuwa J.B. Chabi Orou 《Chinese Journal of Physics (Taipei)》2018,56(3):1089-1104
This paper addresses the issues of nonlinear chemical dynamics modeled by a modified Van der Pol-Duffing oscillator with asymmetric potential. The Melnikov method is utilized to analytically determine the domains boundaries where Melnikov’s chaos appears in chemical oscillations. Routes to chaos are investigated through bifurcations structures, Lyapunov exponent, phase portraits and Poincaré section. The effects of parameters in general and in particular the effect of the constraint parameter β which shows the difference between a nonlinear chemical dynamics order two differential equation and ordinary Van der Pol-Duffing equation are analyzed. Results of analytical investigations are validated and complemented by numerical simulations. 相似文献
10.
In this paper, the parametric adaptive method for controlling the beam halo-chaos in the periodic focusing channels of high-current proton linacs is presented. The study of proton beam halo-chaos based on controlled beam envelope equation and the results of particles-in-cell simulations for macro-particle beam show that the proton beam chaotic envelope as well as the beam rsm radius can be controlled to the beam matched radius using this method.For the Kapchinskij-Vladimirskij (K- V) distribution of initial proton beam, all statistical physical, quantities of the beam halo-chaos are largely reduced. This control method has an advantage of the control halo-chaos since the exterior magnetic field as controlled parameter can be rather easily adjusted in the periodical magnetic focusing channels for the experiment. 相似文献
11.
A. V. Chaplik 《JETP Letters》2010,91(4):188-190
Collective oscillations of an electron-hole plasma in a two-dimensional semimetal have been investigated. It has been shown
that two undamped branches of plasma oscillations exist under certain conditions on the parameters of the structure. Acoustic
plasmons are not damped in a finite wavenumber range. When the Fermi velocities of the electrons and holes are equal to each
other, this range expands to the range of the applicability of the theory (the momentum of the plasmon is much lower than
the Fermi momenta of the particles). 相似文献
12.
A simple model is used to illustrate that a bimolecular Langmuir—Hinshelwood surface reaction with two empty sites in its reaction step, non-equilibrium in the adsorption steps, and coverage independent parameters may lead to sustained oscillatory reaction rates. The two empty sites in the reaction step play an essential role in the establishment of these oscillations. Numerical simulation is used to demonstrate the periodic behavior predicted by the model. Several similar surface reaction models with coverage independent parameters can also yield oscillations. A mechanism with one vacant site in the adsorption steps, two vacant sites in the reaction step and only two dimensionless non-zero parameters may lead to sustained oscillations. 相似文献
13.
This work presents a theoretical study of the energy spectrum of GaAs/AlGaAs concentric double quantum rings, under an applied magnetic field directed perpendicular to the ring plane. The Schrödinger equation for this system is solved in a realistic model consisting of rings with finite barrier potentials. Numerical results show that increasing the magnetic field intensity leads to oscillations in the ground state energy which, in contrast to the usual Aharonov-Bohm oscillations, do not have a well defined period, due to the coupling between inner and outer ring states. However, when one considers an elliptical geometry for the rings, the energy spectra of the inner and outer ring states are decoupled and the periodicity of the oscillations is recovered. 相似文献
14.
GAOYuan LUOXiao-Shu FANGJin-Qing WENGJia-Qiang 《理论物理通讯》2004,42(1):64-68
In this paper, the parametric adaptive method for controlling the beam halo-chaos in the periodic focusing channels of high-current proton linacs is presented. The study of proton beam halo-chaos based on controlled beam envelope equation and the results of particles-in-ceU simulations for macro-particle beam show that the proton beam chaotic envelope as well as the beam rsm radius can be controlled to the beam matched radius using this method. For the Kapchinskij-Vladimirskij (K-V) distribution of initial proton beam, all statistical physical, quantities of the beam halo-chaos are largely reduced. This control method has an advantage of the control halo-chaos since the exterior magnetic field as controlled parameter can be rather easily adjusted in the periodical magnetic focusing channels for the experiment. 相似文献
15.
A meminductor is a new type of memory device developed from the memristor.We present a mathematical model of a flux-controlled meminductor and its equivalent circuit model for exploring the properties of the meminductor in a nonlinear circuit.We explore the response characteristics of the meminductor under the exciting signals of sinusoidal,square,and triangular waves by using theoretical analysis and experimental tests,and design a meminductor-based oscillator based on the model.Theoretical analysis and experiments show that the meminductor-based oscillator possesses complex bifurcation behaviors and can generate periodic and chaotic oscillations.A special phenomenon called the co-existent oscillation that can generate multiple oscillations(such as chaotic,periodic oscillations as well as stable equilibrium) with the same parameters and different initial conditions occurs.We also design an analog circuit to realize the meminductor-based oscillator,and the circuit experiment results are in accordance with the theory analysis. 相似文献
16.
Haibo Xu Guangrui Wang Shigang Chen 《The European Physical Journal B - Condensed Matter and Complex Systems》2001,22(1):65-69
By adjusting external control signal, rather than some available parameters of the system, we modify the straight-line stabilization
method for stabilizing an unstable periodic orbit in a neighborhood of an unstable fixed point formulated by Ling Yang et al., and derive a more simple analytical expression of the external control signal adjustment. Our technique solves the problem
that the unstable fixed point is independent of the system parameters, for which the original straight-line stabilization
method is not suitable. The method is valid for controlling dissipative chaos, Hamiltonian chaos and hyperchaos, and may be
most useful for the systems in which it may be difficult to find an accessible system parameter in some cases. The method
is robust under the presence of weak external noise.
Received 10 January 2001 相似文献
17.
G. E. Norman V. V. Stegailov A. V. Timofeev 《Journal of Experimental and Theoretical Physics》2011,113(5):887-900
The system of equations of motion of dust particles in a near-electrode layer of a gas discharge has been formulated taking
into account fluctuations of the charge of a dust particle and the features of the nearelectrode layer of the discharge. The
molecular dynamics simulation of the system of dust particles has been carried out. Performing a theoretical analysis of the
simulation results, a mechanism of increasing the average kinetic energy of dust particles in the gas discharge plasma has
been proposed. According to this mechanism, the heating of the vertical oscillations of dust particles is initiated by induced
oscillations generated by fluctuations of the charge of dust particles, and the energy transfer from vertical to horizontal
oscillations can be based on the parametric resonance phenomenon. The combination of the parametric and induced resonances
makes it possible to explain an anomalously high kinetic energy of dust particles. The estimate of the frequency, amplitude,
and kinetic energy of dust particles are close to the respective experimental values. 相似文献
18.
Magnetic particles moving freely in a fluid can organize dense phases (3D clusters or linear chains). We analyze the spectrum of magnetic oscillations of a chain of spherical magnetic particles taking into account the magnetic anisotropy of an individual particle for an arbitrary relation between the anisotropy energy and the energy of the dipole interaction of particles. For any relation between these energies, the spectrum contains three branches of collective oscillations: a high-frequency branch and a weakly split doublet of low-frequency branches. The frequency of the high-frequency branch is determined by a stronger interaction, while the frequencies of the low-frequency branches are determined by the weakest interaction. Accordingly, the dispersion is maximal for oscillations formed by the dipole-dipole interaction of particles, which have high frequencies in the case of a strong dipole interaction or low frequencies in the case of a strong anisotropy. 相似文献
19.
Sohrab Behnia Amin Jafari Sojahrood Wiria Soltanpoor Okhtay Jahanbakhsh 《Ultrasonics sonochemistry》2009,16(4):502-511
Nonlinear dynamics of a spherical cavitation bubble was studied. A method based on applying a periodic perturbation to suppress chaotic oscillations is introduced. The relation between this method and dual frequency ultrasonic irradiation is correlated to prove its applicability in applications involving cavitation phenomena. Results indicated its strong impact on reducing the chaotic oscillations to regular ones. The governing parameters are the secondary frequency value and the phase difference between the secondary frequency and the fundamental one. In the end, the possible application of this method in high intensity focused ultrasound tumor ablation as an instance, is discussed accounting for both free bubbles and microbubbles. 相似文献
20.
Yu. A. Kobelev 《Acoustical Physics》2009,55(1):17-26
The problem of monopole, dipole, and rotational scattering of a spatially inhomogeneous time-harmonic sound field by an arbitrary spherical particle is solved for the cases of the medium being a viscous compressible liquid or an isotropic elastic medium. Equations for the spherical mean fields at the particle are obtained. These equations are used to derive the formulas for the scattered fields. Different limiting cases of particle behavior are considered. In particular, it is shown that the dipole scattering is determined by two components of particle oscillations, one of which corresponds to translational oscillatory motion and the other to oscillations of two antiphase monopoles. For these types of particle oscillations, a scattering matrix, which determines the scattering of an arbitrary field by a particle, is constructed. The matrix allows the formalization of the processes of multiple sound scattering by particles and is valid for any distances between the particles down to their contact. 相似文献